When the sun moves around in the sky, the shadow cast by a vertical stick moves on the ground. The tip of the shadow traces some kind of curve. The curve depends on the observation point, and it also ...More: lessons, discussions, ratings, reviews,...

This lesson puts some fun into dimensional analysis! I used to teach converting units/rates by demonstrating on the chalkboard (boring!), but my colleague created this lesson that is sure to spark stu...More: lessons, discussions, ratings, reviews,...

An interactive applet and associated web page showing how to find the area and perimeter of a rectangle
from the coordinates of its vertices. The rectangle can be either parallel to the axes o...More: lessons, discussions, ratings, reviews,...

An interactive applet and associated web page showing how to find the area and perimeter of a square
from the coordinates of its vertices. The square can be either parallel to the axes or rota...More: lessons, discussions, ratings, reviews,...

An interactive applet and associated web page showing how to find the area and perimeter of a trapezoid
from the coordinates of its vertices. The trapezoid can be either parallel to the axes o...More: lessons, discussions, ratings, reviews,...

An interactive applet and associated web page that show the definition and properties of a square
when applied in coordinate geometry.
The applet has a square, and the user can drag any vertex ...More: lessons, discussions, ratings, reviews,...

An interactive applet and associated web page that show the definition and properties of a rectangle in coordinate geometry.
The applet has a rectangle with draggable vertices. As the user re-s...More: lessons, discussions, ratings, reviews,...

An interactive applet and associated web page that show the definition and properties of a trapezoid in coordinate geometry.
The applet has a trapezoid with draggable vertices. As the user re-s...More: lessons, discussions, ratings, reviews,...

In this activity, students investigate the “negative reciprocal” relationship between the slopes of perpendicular lines. The final phase of the activity is appropriate for more advanced students as th...More: lessons, discussions, ratings, reviews,...

An interactive applet and associated web page that show the definition and properties of the bounding box of a polygon or set of points. Also known as the circumscribed rectangle.
The bounding b...More: lessons, discussions, ratings, reviews,...

An interactive applet and associated web page that calculate the area of a triangle using the box method in coordinate geometry.
The applet has a triangle with draggable vertices. As you drag t...More: lessons, discussions, ratings, reviews,...

An interactive applet and associated web page that calculate the area of a triangle using the formula method in coordinate geometry.
The applet has a triangle with draggable vertices. As you dr...More: lessons, discussions, ratings, reviews,...

Let students discover the Fundamental Counting Theorem on their own with this ultra-cute applet from the NTCM Illuminations website. Students dress a bear who is going on vacation to determine the num...More: lessons, discussions, ratings, reviews,...

These mathematics and science-based investigations using the TI-73 with Graph Explorer Software allow students to display and analyze data that they collect. The activities focus on the integration of...More: lessons, discussions, ratings, reviews,...

In this activity, you will order and characterize data using measures such as mean, median, and mode. You'll use the Plop It! tool to build your own data sets to satisfy specific criteria and describe...More: lessons, discussions, ratings, reviews,...

This material is based upon work supported by the
National Science Foundation under Grant DUE-0226284.
Any opinions, findings, and conclusions or recommendations
expressed in this material are those of the author(s)
and do not necessarily reflect the views of the
National Science Foundation.